The present invention is generally related to the field of polarimetry. Measurements of the properties of samples and a medium can be greatly enhanced by taking advantage of the polarization characteristics of electromagnetic radiation. Properties such as diattenuation, retardation, and depolarization can be determined from several polarization measurements. Knowledge of these properties can be useful for a variety of applications where other measured properties do not adequately characterize the sample and medium, such as the extent to which a sample depolarizes radiation.
A polarimeter is a device that measures polarization properties of radiation or the changes of those properties due to propagation through a medium, reflection from a sample, or both. A passive polarimeter measures the polarization state of the incoming radiation. An active polarimeter generates radiation with a controlled polarization state and analyzes the incoming polarization state. A complete polarimeter is one that can make all the measurements necessary to calculate all possible polarization characteristics. A complete passive polarimeter must be able to take a minimum of four measurements needed to calculate the four Stokes parameters and is sometimes referred to as a Stokes polarimeter. A complete active polarimeter must generate four independent polarization states and analyze the Stokes parameters for each generated state. Therefore, a complete active polarimeter must make a minimum of sixteen measurements. Such polarimeters are often complex and do not perform calculations with maximum speed.
Therefore, there is a current need for a high-speed polarimeter of minimal complexity that requires a minimal number of polarization measurements to calculate the linear and circular components necessary to determine the linear and circular characteristics of a sample or medium.